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coconut_random.h

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// Random for COCONUT implementation -*- C++ -*-

// Copyright (C) 2003 Hermann Schichl
//
// This file is part of the COCONUT API.  This library
// is free software; you can redistribute it and/or modify it under the
// terms of the Library GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// Library GNU General Public License for more details.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the Library GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the Library GNU General Public License.

#ifndef __COCONUT_RANDOM_H__
#define __COCONUT_RANDOM_H__

#ifndef DEBUG_RANDOM
#define DEBUG_RANDOM 1
#endif

#include <cmath>
#include <cstdlib>

#define coconut_random  random
#define coconut_seed(A) srandom(A)
#define COCONUT_RAND_MAX RAND_MAX

#define COCONUT_RRAND_MIN -1.e08
#define COCONUT_RRAND_MAX +1.e08

#if DEBUG_RANDOM
#define INIT_SEED    1
#else
#define INIT_SEED    random()
#endif

#define coconut_init_random() srandom(INIT_SEED)

typedef long int rand_t;

inline double d_random()
{
#if (DEBUG_RANDOM > 3)
  double help = (coconut_random()+0.)/(COCONUT_RAND_MAX+0.);
  std::cout << "Random generated: " << help << std::endl;
  return help;
#else
  return (coconut_random()+0.)/(COCONUT_RAND_MAX+0.);
#endif
}

inline double r_random(double l, double u)
{
  l = std::max(l,COCONUT_RRAND_MIN);
  u = std::min(u,COCONUT_RRAND_MAX);
  if(l == u) return l;
  double rndnum = d_random();
  if(l >= 0)
    u = u-l;
  else if(u <= 0)
  {
    double help = l-u;
    l = u;
    u = help;
  }
  else
  {
    double help = l;
    l = 0;
    rndnum = 2*(rndnum-0.5);
    if(rndnum < 0)
      u = -help;
  }
#if (DEBUG_RANDOM > 3)
  std::cout << "r_random: " << l << ", " << u << ", " << rndnum << std::endl;
#endif
  return tan(rndnum*atan(u))+l;
}

inline double r_random(const interval& _i)
{
  return r_random(_i.inf(), _i.sup());
}

#endif /* __COCONUT_RANDOM_H__ */

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